Heretofore, upon an electronic part, which is surface-mountable on a printed circuit board etc., kinds of heat dissipation structures have been proposed by U.S. Pat. No. 7,148,554, and Japanese laid open patent publications 2-309602, 8-181001, 5-217713, and 11-251103 etc.
By U.S. Pat. No. 7,148,554 and Japanese laid open patent publication 2-309602, it is proposed that forming an electrode for heat dissipation at central portion on bottom face of a ceramics substrate of rectangular chip resistor etc. to be spaced from resistor's electrodes, fixing heat dissipating electrode to a conductor pattern for cooling formed on a mounting board such as printed circuit board etc., and dissipating the heats. However, since the heat dissipating electrode is disposed at bottom face of the ceramics substrate, heat dissipating route is limited to one direction from heat generating resistance body to heat dissipating electrode at bottom face, and it seems that there is a problem in efficiency of heat dissipation not being good.
Also, by Japanese laid open patent publications 8-181001 and 5-217713, it is proposed that a resistance body (resistive film) is buried in a resistor supporting body of ceramics material etc. in the shape of a sandwich for improving heat dissipation characteristics. However, it seems that manufacturing process becomes complicated. Also, by Japanese laid open patent publication 11-251103, it is proposed that a resistance body is disposed in a case of insulative material and sealed by cement-like insulative material for improving heat dissipation characteristics.
Further, as to prior art technologies in this technical field, Japanese laid open patent publications 06-275403, 11-251101, 2002-290090, Japanese utility model application 3-028970 (laid open publication 04-123502) micro-film, Japanese laid open patent publications 03-238852, 61-199650, and Japanese utility model application 01-028084 (laid open publication 02-118901) micro-film etc. are known.